Discovering that a sovereign nation such as Iran is behind an attempt to launch a terrorist attack on American soil rises to the level of more concrete and pointed actions. Diplomacy is probably not a workable of viable solution at this time. It hasn’t worked in the past. Sanctions are ineffectual as well.
I do not pretend to present the right solution, however I simply note that it will take real leadership to deliver a decisive response in a way that will make a difference.
Is the current administration up for it? You tell me.